In recent years, televisions installed with the HDMI (High-Definition Multimedia Interface) have become widespread, and it is becoming common to connect a television with a source device via an HDMI cable. A television and a source device connected to each other via an HDMI cable transmit and receive not only video signals and audio signals but also CEC (Consumer Electronics Control) commands.
Use of the CEC command allows controlling a source device from a television and controlling a television from a source device. Therewith use of the CEC command allows users to enjoy convenience, which have not been provided so far. For example, it is possible to automatically switch an input source for the television to a source device that has started to playback content. See, for example, Non Patent Literature 1 for details of HDMI.
Further, because a Micro•HDMI connecter was standardized, it is assumed that use cases where a portable device and a television are connected to each other via HDMI and content played in the portable device is displayed to the television will increase. For example, recent mobile phone terminals have functions for playing still-image content, video-image content, and audio content, so that the recent mobile phone terminals can be used as the source devices. The same applies to portable devices such as PDA, portable digital audio player, and digital camera.
Note that Patent Literatures 1 through 4 each disclose a technique in which a mobile phone terminal provides a user with a notification of a status of the mobile phone terminal itself, such as receiving of a voice phone call and receiving of e-mails.